Kevin Anderson: Increasingly I hear murmurs from some policymakers and scientists that 2°C is too challenging, that we can’t do it – though such concerns are typically expressed away from more public fora. And I can certainly can understand why they are saying this. So what about a 4°C rise? That sounds more viable. The carbon budget is larger and hence the rate of emission reduction is much less challenging.

But what exactly does a 4°C increase in global surface temperature mean? Most of the surface of the earth is water, which heats up more slowly. So it relates to a 5-6 degrees increase in average land temperature. This area of science is very uncertain, but the Hadley Centre [climate change research centre at the Met Office] estimates that, on the hottest days, the temperature would be 6-8 degrees higher in China, 8-10 degrees in Europe and 10-12 degrees in New York. Such unprecedented increases would give rise to host of issues about how the aging infrastructure of our cities could deliver even survival-level services.

And what about the people who have not caused the problem, in the lower latitudes? It is hard to be accurate, but the Hadley Centre estimates that, for farmers in lower latitudes, a 40% reduction in yields of maize and rice characterises their 4°C impacts.

This is a world that we have to avoid at all costs. Many scientists suggest that a 4°C rise is incompatible with an organised global community. It is beyond “adaptation.” Yet this review of 4°C temperature rise does not take into account possible feedbacks and other discontinuities, which on average are anticipated to make the situation worse still.

So a 4 degrees future is something we must avoid. And that takes us back to 2 degrees – albeit with increasingly lower probabilities of achieving even this. What does 2°C imply for the wealthy parts of the world, the OECD countries? It means a 10% reduction in emissions every single year: a 40% reduction in the next few years and a 70% reduction within the decade. Such reductions are necessary if poor parts of the world are to have a small emission space to help their welfare and wellbeing improve.

Despite the coherence of this analysis, I am repeatedly advised that such levels of mitigation are impossible. At the same time, living as a civilised global community with a 4 degrees rise would also seem impossible. In other words: the future is impossible!

So what do we do? We have to develop a different mind-set – and quickly. The impossibility we face on mitigation may open us to conceiving of different futures – moving beyond the reductionist thinking of the twentieth century, and towards new ways of framing issues in the twenty-first century.

GL: You have pointed out that, counting roughly, the top 20% of the world population by income are responsible for 80% of emissions; that the top 20% of that top 20% are responsible for 80% of the 80% of emissions, and so on. And your argument is that emissions reductions policies have to be applied to those people, i.e. those who are responsible for the actual emissions. Is that correct?

KA: Yes. Many of the policies put in place – the emissions trading scheme, or proposals for carbon taxes – are universal. They do not differentiate between high and low emitters. I would argue that that is not appropriate. In the UK, to say nothing of developing countries, many people struggle to pay their energy bills, and have fairly low emissions anyway. So why are we expecting people who have barely contributed to the problem to put up with the pain of reducing their already-low level of emissions?

As it stands, the mechanisms favoured by the wealthy high emitters are principally price-based; mechanisms we, the wealthy high emitters, can buy our way out of.

This is neither fair, nor will it work. The emissions have to be reduced from those people primarily responsible for emitting.

A whole-scale switch to a low-carbon energy economy will require a broad transformation of infrastructure worldwide. Photo of machinery in the Alberta tar sands by Kris Krug.

GL: Climate scientists are coming under enormous political pressure. You have spoken about scientists coming under pressure to produce unrealistic scenarios; there is also the pressure that climate scientists have been put under by vicious public witch-hunts conducted by climate science deniers. Is there more that the rest of us, the non-scientists, could do, to support scientists in resisting this pressure?

KA: One of the problems for scientists – and it is something that the “sceptics” have latched on to – is that science does not provide certainties: it seldom provides black and white views of the world. Yet schools, and particularly the media, interpret science as being about certain truths. This misunderstands what science can offer: it is about evolving a better understanding of the issues being considered – and in doing so it will typically contain uncertainties and ranges of results rather than a precise and unarguable answer. The “sceptics,” by contrast, present a much more categorical view, that feeds into what the public want to hear and the media can easily peddle.

The argument for more action, sooner. From a presentation by Alice Bows.

The public and media appear often to struggle with the concept of science as an evolving process. Consensus views emerge and evolve. This doesn’t mean understanding is flipping from one thing to another, though this is often how it is reported and interpreted. This is a real problem for the science underpinning climate change: it is attempting to shed light on a complicated, complex and system-level issue, and consequently uncertainties abound. By its very nature, understanding climate change is open to being undermined by Machiavellian “sceptics.” It is much easier to be cynically critical of climate science than it is to do good science.

If the public were more understanding of, and accepting of, the evolving nature of science, and the uncertainties, it would likely be easier to have more constructive conversations with the public, media and policymakers. As scientists we should be as open as possible. Take the “climategate” affair.[2] It was appalling for some of the individual scientists involved: they are normal human beings who had dedicated their careers to delivering sound science – yet their lives were ripped apart. And in fact this process had been going on for many years beforehand.

There are an estimated 176 square kilometres of tailings ponds, pictured frozen here, that hold the waste product of bitumen development in the tar sands. Photo by Kris Krug.

Scientists have long been subjected to unpleasant, threatening email campaigns – and I talk about this from some personal experience. But although “climategate” was very destructive for people personally, I take the view that it had a silver lining. Since then, the scientific community has collectively become more open about its analyses and findings. The more open we can be about our work, about our discussions and disagreements, the better that is for society. This is a social issue: it is not just about science. So I think some good came out of the affair.

Furthermore, although the climate “sceptics” are often well funded and are organised around a much easier destructive agenda, they have been unable really to dent the scientific understanding of climate change. The “sceptics” have certainly scared and influenced some policymakers, and in that way have further delayed mitigation efforts – for which poorer people living in more vulnerable communities will inevitably suffer. However, for science, the repercussions of their efforts have been to deliver a much more open and resilient science community and demonstrate the robustness of the science underpinning concerns about climate change. So, in a strange way, they are to be thanked.

■ The Campaign Against Climate Change web site is here; more on last month’s conference here.

[2] “Climategate” began with the publication by climate science deniers, just before the 2009 United Nations climate change summit at Copenhagen, of hacked emails by Phil Jones, a leading climate scientist at the University of East Anglia, and others. By presenting selected passages from the emails in a way designed deliberately to distort their meaning, climate science deniers falsely claimed that Jones and others had tried to suppress the results of research that questioned some standard findings of climate science. The charges were widely reported in the days prior to the conference, together with a tide of false accusations against Jones, questioning his professional integrity. The identity of the hackers was never established. Jones and his colleagues were cleared of any wrongdoing in an enquiry by the university authorities.